A food microorganism rapid detection device for food detection

Abstract

The application provides a food microorganism rapid detection device for food detection, and relates to the technical field of detection devices, which comprises a colony counter body, a circular mounting groove is arranged on the colony counter body, a lamp holder is fixedly arranged at the bottom of the circular mounting groove, three circle layer lighting assemblies are arranged on the lamp holder, the three circle layer lighting assemblies comprise an inner circle ultraviolet lamp groove, a middle circle side light lamp groove and an outer circle light supplementing lamp groove, the application completely solves the problems of high microcolony missing detection rate and inaccurate edge counting of a traditional colony counter, the inner circle 15° centripetal inclined ultraviolet lamp groove provides uniform vertical ultraviolet light, the middle circle 30° centripetal inclined white light lamp groove forms a side light bright and dark boundary effect, the contrast between the colony and the culture medium is increased by more than 4 times, and the real colony can be physically distinguished from false positive impurities such as bubbles and fat balls, and the outer circle light supplementing lamp groove cooperates with a 45° mirror surface light reflection arc plate to increase the brightness of the edge area of the culture dish by more than 3 times.

Description

Technical Field

[0001] This invention belongs to the field of detection device technology, and more specifically, relates to a rapid detection device for food microorganisms in food testing. Background Technology

[0002] Microbiological testing of food is a core aspect of food safety supervision. Among these methods, plate count is currently the internationally accepted standard for quantitative microbial detection, widely used in the routine testing work of food production enterprises, third-party testing institutions, and regulatory departments. With the increasing number of food batches tested each year, higher demands are being placed on the accuracy, efficiency, reliability, and ease of maintenance of colony counters. Currently, commercially available colony counters exhibit the following specific technical problems in actual batch food testing applications: The inherent defects in the lighting structure lead to a high rate of missed detection for tiny colonies and inaccurate counting in the edge areas. In routine total bacterial count testing scenarios, the typical colony diameter of pathogenic bacteria such as E. coli and Salmonella is only 0.1-0.3 mm. Moreover, microorganisms have significant wall-adaptive growth characteristics, with more than 30% of colonies concentrated in the 80-90 mm annular area at the edge of the petri dish. Existing colony counters mostly use single-ring vertical lighting or single-angle centripetal tilted lighting structures. Vertical lighting cannot create a light-dark boundary at the edge of tiny colonies, resulting in insufficient contrast between colonies and transparent culture medium. Colonies as small as 0.1 mm are very easy to miss. Although single-angle centripetal tilted lighting can improve the contrast in the central area, all the light converges to the center, resulting in a dark area at the edge of the petri dish. The brightness of the edge area is less than 30% of that in the central area, making it impossible to clearly identify colonies at the edge. The overall missed detection rate exceeds 20%.

[0003] Fixed optical structures cannot be adapted to different types of culture media, resulting in a high misclassification rate. Food microbiology testing involves a variety of culture media with vastly different optical properties, such as transparent PCA agar, translucent blood agar, and opaque MacConkey agar. Existing colony counters all use fixed optical glass structures, which cannot be adjusted according to the reflective and absorption characteristics of different culture media. For blood agar, the fixed glass amplifies the granular background reflection produced by red blood cells, easily misclassifying reflective points as colonies. For dark culture media such as MacConkey, the excessively high background brightness leads to insufficient contrast between colonies and background, making it difficult to distinguish different types of colonies, with an overall misclassification rate exceeding 15%.

[0004] Fixed glass bases are prone to cross-contamination and have high maintenance costs. Food testing requires extremely high aseptic operation, and the contact parts of the equipment need to be thoroughly disinfected after each test. Most existing colony counters have glass bases that are integrated into the equipment body and cannot be disassembled. The gaps between the glass and the body are prone to the accumulation of culture medium residue and condensation, which are difficult to clean and disinfect thoroughly, and can easily cause cross-contamination between different samples. At the same time, the glass base is easily scratched by the petri dishes during long-term use. Once damaged, the entire glass assembly needs to be disassembled and replaced, which is costly and time-consuming. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a rapid food microbial detection device for food testing, which solves the problems of high false negative rates for small and marginal colonies in traditional colony counters, easy failure of electronic switches in harsh laboratory environments and short lifespan of ultraviolet lamp beads, high false positive rates due to the inability of fixed optical structures to adapt to different culture media, and high maintenance costs due to the ease of cross-contamination of fixed bases.

[0006] A rapid food microbial detection device for food testing includes a colony counter body with a circular mounting groove. A lamp holder is fixed at the bottom of the circular mounting groove, and the lamp holder has a three-ring illumination assembly to achieve precise illumination without blind spots, solving the problems of center overexposure and edge darkness in traditional single-angle illumination. The three-ring illumination assembly includes an inner ultraviolet lamp slot, a middle sidelight lamp slot, and an outer supplementary light lamp slot. High-purity long-wave ultraviolet LED beads, high-brightness cool white LED beads, and supplementary light LED beads are respectively installed in the inner ultraviolet lamp slot, the middle sidelight lamp slot, and the outer supplementary light lamp slot, respectively realizing the three core functions of fluorescence excitation, side lighting for small colonies, and edge supplementary lighting. The upper surface of the lamp holder has a double-shield switching mechanism to achieve purely physical mode switching, completely avoiding the environmental adaptability defects of electronic switches. The double-shield switching mechanism includes a first light-shielding plate and a second light-shielding plate, which are magnetically connected to ensure precise and error-free switching, completing the mode conversion in one second. The upper end of the lamp holder is equipped with a detachable high-transparency glass base, which facilitates thorough disinfection and individual replacement in case of damage. The lower end of the high-transparency glass base is fitted with a replaceable optical ring sleeve, which can be flexibly adapted to the optical characteristics of different culture media, greatly improving colony contrast.

[0007] Preferably, the inner ring UV lamp slot, the middle ring side light lamp slot, and the outer ring supplemental light lamp slot are coaxially arranged from the inside to the outside on the upper surface of the lamp holder, ensuring that the light emission axes of all LED beads are precisely converged at the center of the bottom of the culture dish, avoiding uneven illumination caused by light deviation. The inner ring UV lamp slot, the middle ring side light lamp slot, and the outer ring supplemental light lamp slot are all U-shaped slots with upward openings, forming a 0.2mm interference fit with the through-hole LED beads, allowing for secure fixation without glue or screws. If a single LED bead is damaged, it can be directly removed and replaced with tweezers, resulting in extremely low maintenance costs. The bottom of the inner ring UV lamp slot is inclined at 15° to the center of the lamp holder, providing uniform vertical UV light to ensure that the target colonies are fully excited to produce fluorescence. The bottom of the middle ring side light lamp slot is inclined at 30° to the center of the lamp holder, creating a unique light-dark boundary effect, increasing the contrast between 0.1mm-level micro-colonies and the culture medium by more than 4 times.

[0008] Preferably, the outermost edge of the lamp holder is integrally injection molded with a reflective arc plate that is inclined inward at 45°. The inner side of the reflective arc plate is mirror polished, which can refract all the light scattered outward by the outer ring supplementary light beads inward, so that the light completely covers the 80-90mm area of ​​the outermost ring of the culture dish, increasing the brightness of the edge area by more than 3 times, and achieving a uniformity of illumination of 97% across the entire area, thus completely solving the problem of missed detection of edge colonies caused by microbial growth towards the wall.

[0009] Preferably, the first light-shielding plate is a circular flat plate with the same diameter as the outer diameter of the inner ultraviolet lamp slot, which can completely block all ultraviolet lamp beads in the inner ring to achieve a pure white light counting mode. The second light-shielding plate is an annular flat plate with the same inner diameter as the outer diameter of the inner ultraviolet lamp slot and the same outer diameter as the outer diameter of the middle ring side light slot, which can completely block all white light lamp beads in the middle ring to achieve a pure ultraviolet fluorescence identification mode. Four miniature neodymium iron boron magnets are embedded in the lower surface of both the first and second light-shielding plates, and four magnets of the same polarity are embedded in the corresponding positions of the lamp holder. Automatic positioning and fixation are achieved through the attraction of opposite poles, preventing sliding or misalignment during use, and disassembly and assembly require no tools.

[0010] Preferably, the outer ring of the high-transparency glass base is fixedly provided with a magnetic ring. The high-transparency glass base is magnetically connected to the colony counter body through the magnetic ring, which can be quickly disassembled and assembled in one second. After removal, it can be directly wiped with alcohol or sterilized by high pressure. There are no dead corners for cleaning, and cross-contamination between different samples is eliminated. If the glass base is scratched, cracked or otherwise damaged, only the base needs to be replaced. There is no need to disassemble and repair the entire device.

[0011] Preferably, the optical ring sleeve is a ring structure with a solid bottom, and its outer diameter is consistent with the outer diameter of the high-transparency glass base, ensuring that all light passes through the ring sleeve material and achieving a stable optical adjustment effect. The sides are finished with a matte black coating to block stray light leaking from the LED beads from the sides, preventing eye injury to operators and glare interference. A semi-circular notch is provided on the side for easy replacement by the operator using their fingers, and the replacement process does not require moving the culture dish, thus completely preventing culture medium contamination. The optical ring sleeve can be any one of a high-transparency ring sleeve, a frosted diffused ring sleeve, or a neutral gray ring sleeve, respectively adapted to transparent, semi-transparent, and dark culture media, and can specifically eliminate background reflection and improve colony contrast.

[0012] Compared with the prior art, the present invention has the following beneficial effects: In this invention, by employing a three-tiered coaxial illumination structure with differentiated tilt angles, the core problems of high false negative rates for tiny colonies and inaccurate edge counting in traditional colony counters are completely solved. The inner 15° centripetally tilted UV lamp trough provides uniform vertical UV light, while the middle 30° centripetally tilted white light lamp trough creates a side light-dark boundary effect, increasing the contrast between 0.1mm-level tiny colonies and the culture medium by more than 4 times. This allows for the physical differentiation of real colonies from false positive impurities such as bubbles and fat globules. The outer supplementary lighting trough, combined with a 45° mirrored reflective arc plate, increases the brightness of the edge area of ​​the culture dish by more than 3 times, improving the uniformity of illumination across the entire area. This makes edge colonies growing towards the wall clearly visible, reducing the overall false negative rate.

[0013] In this invention, a purely physical magnetic switching mechanism composed of a first light-shielding plate and a second light-shielding plate completely avoids the failure risk of electronic shunt switches in harsh laboratory environments. The light-shielding plate, made of pure ABS plastic, is not affected by high humidity, alcohol vapor, or disinfectant corrosion, and its service life is consistent with that of the equipment body. It can be used for a long time without mechanical switching failures. At the same time, it avoids the problem of accelerated light decay caused by frequent switching of UV lamp beads, extending the service life of UV lamp beads from 3-6 months to more than 20,000 hours. It also eliminates the 3-5 minute preheating waiting time for each switch, effectively improving the detection efficiency of single batches of samples and significantly reducing equipment maintenance costs and detection cycles.

[0014] In this invention, by setting a replaceable optical ring sleeve structure at the lower end of a high-transparency glass base, precise adaptation to culture media with different optical properties is achieved. For transparent PCA agar, semi-transparent blood agar, and opaque MacConkey agar, high-transparency, frosted diffuse, and neutral gray ring sleeves with different transmittance can be selected respectively. Through gap matching, replacement can be achieved in seconds, and the replacement process does not require moving the culture dish, so it will not cause any culture medium contamination. Different types of ring sleeves can also be stacked and used, solving multiple optical problems at the same time.

[0015] In this invention, the use of a magnetically detachable high-transparency glass base structure completely solves the problems of high risk of cross-contamination and high maintenance cost of fixed bases. The glass base is magnetically connected to the counter body via a rubber magnetic strip, allowing for assembly and disassembly in one second. After removal, it can be directly wiped with alcohol or autoclaved, leaving no cleaning dead corners and eliminating cross-contamination between different samples. The 5mm standard auxiliary grid etched on the upper surface of the base helps inspectors count in an orderly manner by area, avoiding omissions and duplicate counts. If the base is scratched, cracked, or damaged, only the base needs to be replaced, without the need for disassembly and repair.

[0016] In this invention, the overall design of the purely physical structure significantly improves the repeatability of test results and the inherent safety of the equipment. All LEDs are always in a constant rated operating state, and the light intensity output is not affected by switching current impact, voltage fluctuations, and temperature changes. The repeatability error of the test results is controlled within 2%, which fully meets the accuracy requirements of the GB4789 series of national standards. Operators do not come into contact with any live parts during mode switching and use. Even if the internal circuit of the equipment malfunctions, it will not cause electric shock to the operator. It completely eliminates the safety hazards of wet hands operation and flammable disinfectant environment in the laboratory. It is an inherently safe equipment that truly meets the needs of food testing laboratories. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the colony counter body of the present invention; Figure 3 This is a schematic diagram of the high-transparency glass base of the present invention; Figure 4 This is a schematic diagram of the structure of the second light-shielding plate of the present invention; Figure 5 This is a schematic diagram of the structure of the lamp holder of the present invention; Figure 6 This is a schematic diagram of the structure of the first light-shielding plate of the present invention; Figure 7 This is a schematic diagram of the structure of the long-wave ultraviolet LED lamp bead of the present invention; Figure 8 This is a schematic diagram of the structure of the high-brightness cool white LED lamp bead of the present invention.

[0018] In the diagram, the correspondence between the component names and the attached drawing numbers is as follows: 1. Lamp holder; 2. Long-wave ultraviolet LED bead; 3. Inner ring ultraviolet lamp slot; 4. High-brightness cool white LED bead; 5. Middle ring side light slot; 6. Supplemental light LED bead; 7. Outer ring supplemental light slot; 8. Reflector arc plate; 9. First light shield; 10. Second light shield; 11. Colony counter body; 12. Optical ring sleeve; 13. Magnetic ring; 14. High-transparency glass base; 15. Auxiliary grid. Detailed Implementation

[0019] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0020] Please see Figure 1 - Figure 8 This invention provides a rapid food microbial detection device for food testing, including a colony counter body 11, a lamp holder 1 fixedly installed inside the colony counter body 11, a three-ring illumination assembly disposed on the lamp holder 1, a double light-shielding plate switching mechanism magnetically connected to the lamp holder 1, a high-transparency glass base 14 disposed on the upper end of the lamp holder 1, and a replaceable optical ring sleeve 12 sleeved on the lower end of the high-transparency glass base 14. The three-ring illumination assembly includes an inner ultraviolet lamp groove 3, a middle side light lamp groove 5, and an outer supplementary light lamp groove 7 coaxially disposed on the upper surface of the lamp holder 1. High-purity long-wave ultraviolet LED beads 2 are uniformly installed in the inner ultraviolet lamp groove 3, high-brightness cool white LED beads 4 are uniformly installed in the middle side light lamp groove 5, and supplementary light LED beads 6 are uniformly installed in the outer supplementary light lamp groove 7.

[0021] Specifically, refer to Figure 1 and Figure 2 As shown, the upper surface of the colony counter body 11 is provided with a circular mounting groove. The lamp holder 1 is a one-piece injection molded white ABS annular disc, which is fixedly installed at the bottom of the circular mounting groove. The center of the lamp holder 1 is completely coincident with the center of the circular mounting groove, ensuring that the subsequent light can accurately illuminate the central area of ​​the petri dish. The upper surface of the lamp holder 1 is provided with an inner ring ultraviolet lamp groove 3, a middle ring side light lamp groove 5 and an outer ring supplementary light lamp groove 7, which are coaxially formed from the inside to the outside. All three lamp grooves are U-shaped grooves with the opening facing upwards, which can achieve a firm fixation of the lamp beads without glue or screws.

[0022] It should be noted that the reference Figure 5 and Figure 7As shown, the bottom surfaces of the three rings of lamp slots have different inclination angles, and all inclination angles are based on the horizontal plane and tilted in the corresponding direction. Among them, the bottom surface of the inner ring ultraviolet lamp slot 3 is tilted at 15° towards the center of the lamp holder 1. Twelve straight-insertion high-purity long-wave ultraviolet LED beads 2 are evenly inserted into the slot. The light emission axis of the lamp beads is precisely converged 20mm directly above the center of the lamp holder 1. This position is exactly the center of the bottom of the petri dish placed on the high-transparency glass base 14. The middle ring side-light lamp slot 5 The bottom surface is tilted 30° towards the center of the lamp holder 1. Twelve through-hole 6500K high-brightness cool white LED beads 4 are evenly inserted into the groove, and are staggered with the inner ring long-wave ultraviolet LED beads 2 to avoid mutual light blocking. Twelve through-hole 6500K supplementary light LED beads 6 are evenly inserted into the groove of the outer ring supplementary light groove 7. All LED beads are directly inserted into the corresponding U-shaped groove through interference fit. When a single LED bead is damaged, it can be directly pulled out and replaced with tweezers, and the maintenance cost is extremely low. The outermost edge of the lamp holder 1 is integrally injection molded with a reflective arc plate 8. The reflective arc plate 8 is tilted inward at 45° and its inner side is mirror polished. The reflective arc plate 8 can refract the light scattered outward by the supplementary LED beads 6 in the outer ring supplementary light groove 7 inward, so that the light completely covers the entire bottom surface of the high-transparency glass base 14, completely eliminating the dark area at the edge of the culture dish, ensuring that the uniformity of the light in the whole area reaches more than 97%, and solving the problem of insufficient brightness at the edge of the traditional centripetal tilting lamp holder.

[0023] refer to Figure 4 and Figure 6 As shown, the dual-shield switching mechanism includes a first light-shield plate 9 and a second light-shield plate 10. Both light-shield plates are circular flat plates made of black ABS material and are detachably connected to the lamp holder 1 by magnetic attraction. The diameter of the first light-shield plate 9 is the same as the outer diameter of the inner ultraviolet lamp groove 3. Four miniature neodymium iron boron magnets are embedded on its lower surface. Four magnets of the same polarity are embedded in the corresponding position of the lamp holder 1. Fixing is achieved by attraction of opposite polarities. When high-brightness cool white LED beads 4 are needed for lighting, the first light-shield plate 9 is placed in the center of the lamp holder 1. The first light-shield plate 9 can completely block all long-wave ultraviolet LED beads 2 in the inner ultraviolet lamp groove 3. At this time, only the high-brightness cool white LED beads 4 in the middle side light groove 5 and the supplementary light LED beads 6 in the outer supplementary light groove 7 work. The second light-shielding plate 10 is an annular flat plate. Its inner diameter is the same as the outer diameter of the inner ultraviolet lamp groove 3, and its outer diameter is the same as the outer diameter of the middle side light lamp groove 5. Four miniature neodymium iron boron magnets are also embedded on its lower surface. When long-wave ultraviolet LED beads 2 are needed for lighting, the second light-shielding plate 10 is placed on the lamp holder 1. The second light-shielding plate 10 can completely block all the high-brightness cool white LED beads 4 in the middle side light lamp groove 5. At this time, only the long-wave ultraviolet LED beads 2 in the inner ultraviolet lamp groove 3 and the supplementary LED beads 6 in the outer supplementary light lamp groove 7 work. The magnetic connection method can ensure that the two light-shielding plates will not be misaligned during use, and the switching operation is simple and convenient. The mode switching can be completed in a few seconds. Using the first light-shielding plate 9 and the second light-shielding plate 10 can significantly extend the service life of the long-wave ultraviolet LED bead 2 and eliminate the preheating waiting time. The core characteristic of the long-wave ultraviolet LED bead 2 is that frequent switching will accelerate its light decay rate by more than 3 times, and it requires a preheating time of 3-5 minutes after each turn-on to reach a stable light power output. Frequent switching of ultraviolet mode will cause the ultraviolet LED bead to need to be replaced within 3-6 months. When using the light-shielding plate for switching, the ultraviolet LED bead can remain in a constant state without frequent switching.

[0024] refer to Figure 2 and Figure 3 As shown, the high-transparency glass base 14 is set at the upper end of the lamp holder 1. Its outer diameter is adapted to the inner diameter of the circular mounting groove on the upper surface of the colony counter body 11. A magnetic ring 13 is fixedly set on the outer ring of the high-transparency glass base 14. The magnetic ring 13 is made of rubber magnetic strip and is fixed to the side wall of the high-transparency glass base 14 by adhesive. The magnetic ring 13 is magnetically connected to the colony counter body 11, realizing the quick installation and disassembly of the high-transparency glass base 14. An auxiliary grid 15 is etched on the upper surface of the high-transparency glass base 14. The auxiliary grid 15 is composed of mutually perpendicular scale lines. The side length of each grid is 5mm. It is used to assist the inspectors in counting colonies by area and avoid missing and double counting. An optical ring sleeve 12 is fitted at the lower end of the high-transparency glass base 14. The optical ring sleeve 12 and the high-transparency glass base 14 are fitted with a gap, and the optical ring sleeve 12 of different materials can be quickly replaced according to different detection requirements. The optical ring sleeve 12 is a ring structure with a solid bottom, and its outer diameter is the same as that of the high-transparency glass base 14.

[0025] Specifically, refer to Figure 3As shown, based on the optical characteristics of different culture media, the optical annular sleeve 12 can be selected from the following three types: High-transparency annular sleeve, made of optical-grade PMMA material with a transmittance ≥92%, with both upper and lower surfaces mirror-polished, suitable for the detection of transparent PCA agar and nutrient agar, maximizing light transmittance and improving the contrast of 0.1mm-level microbacterial colonies; and frosted diffuse annular sleeve, made of high-transparency PMMA material with embedded micron-level silica diffuser particles, with a finely frosted finish on the lower surface (Ra0.8) and a mirror-like upper surface, suitable for... Used for the detection of blood agar and chocolate agar, it can convert directional direct light into uniform diffuse light, eliminate the granular background reflection produced by red blood cells, clearly show the boundary of hemolysis ring, and facilitate the identification of β-hemolysis and α-hemolysis. The neutral gray ring sleeve is made of PMMA material with uniformly added carbon black pigment, and is divided into three standard transmittance levels of 70%, 50%, and 30%. Both the upper and lower surfaces are mirror polished. It is suitable for the detection of MacConkey agar, SS agar, and eosin methylene blue agar, respectively, and can uniformly reduce the background brightness and improve the contrast between colonies and the background.

[0026] It should be noted that the optical ring sleeve 12 has a semi-circular notch on its side, which makes it easy for operators to remove and replace it with their fingers. The replacement process does not require moving the culture dish and will not contaminate the culture medium. In addition, different types of optical ring sleeves 12 can be used in combination. For example, stacking a frosted diffuse ring sleeve with a neutral gray ring sleeve with 50% transmittance can solve the problems of reflection and background brightness of blood agar at the same time, and further improve the detection accuracy.

[0027] Working principle: The first step, when performing routine total bacterial count testing, is for the operator to select the corresponding optical ring sleeve 12 according to the type of culture medium to be tested. For the most commonly used transparent PCA agar or nutrient agar, a high-transparency ring sleeve is selected and inserted into the lower end of the high-transparency glass base 14 from bottom to top. It is automatically positioned by the gap fit and no additional fixation is required.

[0028] Then, the first light-shielding plate 9 is placed in the center of the lamp holder 1 and automatically attached and fixed by magnetic attraction. The first light-shielding plate 9 will completely block all the long-wave ultraviolet LED beads 2 in the inner ultraviolet lamp groove 3. At this time, the power supply of the device is turned on, and the high-brightness cool white LED beads 4 and the supplementary light LED beads 6 in the three rings of beads are simultaneously in rated working state. The high-brightness cool white LED beads 4 in the middle ring, which are tilted 30° inward, emit directional side light, which is transmitted from the lower side of the bottom of the petri dish through the culture medium, forming a bright highlight band at the edge of the 0.1-0.3mm-level tiny flat colonies, and casting a very shallow asymmetrical shadow on the other side of the colony. This light and dark boundary effect can enhance the contrast between the colony and the transparent culture medium. The illumination is increased to more than four times that of traditional vertical lighting, making tiny colonies that were almost blended into the background instantly visible. Since impurities such as transparent bubbles and fat globules have homogeneous optical structures, they do not produce such asymmetrical light and dark boundaries. Inspectors can quickly distinguish between real colonies and false positive impurities, greatly reducing the misjudgment rate. The light emitted by the supplementary LED beads 6 on the outer ring is refracted by the reflective arc plate 8 and evenly covers the outermost 80-90mm area of ​​the petri dish, completely eliminating the edge dark area of ​​traditional centripetal lighting. With the help of the 5mm side length auxiliary grid 15 on the high-transparency glass base 14, inspectors can divide the petri dish into 12 equal fan-shaped areas and count them in sequence, completely avoiding the problems of missed counts and duplicate counts.

[0029] In the second step, during fluorescent colony detection, the operator first removes the high-transmittance ring sleeve and replaces it with a narrow-band ultraviolet filter ring sleeve. This filter sleeve only allows 365nm long-wave ultraviolet light to pass through, completely filtering out stray light. Then, the first light-shielding plate 9 is removed and replaced with the second light-shielding plate 10. The second light-shielding plate 10 completely blocks all the high-brightness cool white LED beads 4 in the middle ring side light slot 5. At this time, the inner ring 15° near-vertical long-wave ultraviolet LED beads 2 continuously output stable ultraviolet light, evenly illuminating the bottom of the culture dish. The vertical ultraviolet light can penetrate the entire colony, exciting target pathogenic bacteria such as Listeria, Staphylococcus aureus, and Escherichia coli O157 to produce specific fluorescence. Meanwhile, the weak white light background provided by the outer ring supplementary light LED beads 6 can clearly display the outline of the culture dish and the auxiliary grid 15, avoiding the problem of not being able to locate colonies against a pure black background.

[0030] Because it uses a light-shielding plate for switching instead of an electronic switch, the UV lamp beads always remain on, eliminating the need for a 3-5 minute warm-up time. You can start observing immediately after switching modes, and the light power output is stable throughout its life. The fluorescence signal intensity is extremely consistent, and the false positive rate can be reduced to below 1%.

[0031] In the third step, when conducting initial screening of large batches of samples, the operator removes two light-shielding plates, and twenty-four LED beads are lit simultaneously. White light and ultraviolet light are mixed to irradiate the culture dishes. The inspectors can simultaneously observe the morphology, size, color, and edge characteristics of the colonies through white light and observe the fluorescence characteristics of the colonies through ultraviolet light. Colony counting and preliminary identification can be completed in one observation without the need to repeatedly switch modes, thus improving the efficiency of single batch sample testing. After the test is completed, the high-transparency glass base 14 is directly removed from the colony counter body 11 and disinfected with alcohol or subjected to high-pressure sterilization to prevent cross-contamination between different samples. If the high-transparency glass base 14 is scratched, broken, or otherwise damaged, only the base needs to be replaced, without the need to repair the entire equipment, resulting in extremely low maintenance costs.

[0032] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A rapid detection device for food microorganisms, comprising a colony counter body (11), characterized in that: The colony counter body (11) is provided with a circular mounting groove, and a lamp holder (1) is fixedly provided at the bottom of the circular mounting groove. The lamp holder (1) is provided with a three-ring lighting component. The three-ring lighting assembly includes an inner ultraviolet lamp slot (3), a middle side light lamp slot (5) and an outer supplementary light lamp slot (7). The inner ultraviolet lamp slot (3), the middle side light lamp slot (5) and the outer supplementary light lamp slot (7) are respectively equipped with high-purity long-wave ultraviolet LED beads (2), high-brightness cool white LED beads (4) and supplementary light LED beads (6). The upper surface of the lamp holder (1) is provided with a double light shield switching mechanism, which includes a first light shield (9) and a second light shield (10), and the first light shield (9) and the second light shield (10) are magnetically connected. The upper end of the lamp holder (1) is provided with a detachable high-transparency glass base (14), and the lower end of the high-transparency glass base (14) is provided with a replaceable optical ring sleeve (12).

2. The rapid food microbial detection device for food testing as described in claim 1, characterized in that, The inner ultraviolet lamp slot (3), the middle side light lamp slot (5), and the outer supplementary light lamp slot (7) are coaxially arranged from the inside to the outside on the upper surface of the lamp holder (1).

3. The rapid food microbial detection device for food testing as described in claim 2, characterized in that, The inner ring ultraviolet lamp groove (3), the middle ring side light lamp groove (5) and the outer ring supplementary light lamp groove (7) are all U-shaped grooves with openings facing upwards.

4. The rapid food microbial detection device for food testing as described in claim 3, characterized in that, The bottom of the inner ring ultraviolet lamp groove (3) is inclined at 15° to the center of the lamp holder (1), and the bottom of the middle ring side light lamp groove (5) is inclined at 30° to the center of the lamp holder (1).

5. The rapid food microbial detection device for food testing as described in claim 4, characterized in that, The outermost edge of the lamp holder (1) is integrally injection molded with a reflective arc plate (8) that is inclined inward at 45°, and the inner side of the reflective arc plate (8) is mirror polished.

6. The rapid food microbial detection device for food testing as described in claim 5, characterized in that, The first light-shielding plate (9) is a circular flat plate with the same diameter as the outer diameter of the inner ultraviolet lamp groove (3); the second light-shielding plate (10) is an annular flat plate with the same inner diameter as the outer diameter of the inner ultraviolet lamp groove (3) and the same outer diameter as the outer diameter of the middle side light groove (5).

7. The rapid food microbial detection device for food testing as described in claim 6, characterized in that, The lower surfaces of the first light-shielding plate (9) and the second light-shielding plate (10) are each embedded with four miniature neodymium iron boron magnets, and the corresponding positions of the lamp holder (1) are embedded with four magnets of the same polarity.

8. The rapid food microbial detection device for food testing as described in claim 7, characterized in that, The outer ring of the high-transparency glass base (14) is fixedly provided with a magnetic ring (13), and the high-transparency glass base (14) is magnetically connected to the colony counter body (11) through the magnetic ring (13).

9. The rapid food microbial detection device for food testing as described in claim 8, characterized in that, The optical ring sleeve (12) is a ring structure with a solid bottom. Its outer diameter is the same as that of the high-transparency glass base (14). The side is treated with black matte finish and has a semi-circular notch.

10. The rapid food microbial detection device for food testing as described in claim 9, characterized in that, The optical ring sleeve (12) is any one of a high-transparency ring sleeve, a frosted diffuse ring sleeve, or a neutral gray ring sleeve.

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